Inclusion criteria:

1. Documented diagnosis of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), idiopathic inflammatory myopathy (IIM; including polymyositis, dermatomyositis, anti-synthetase syndrome), Sjogren's syndrome (pSS), or mixed connective tissue disease (MCTD) in accordance with internationally recognized classification criteria
2. Diagnosis of ILD on High Resolution Computed Tomography (HRCT) with disease extent of greater than or equal to greater than or equal to 10% of the whole lung (WLILD)
3. Evidence of ILD progression in the previous 24 months
4. Must be currently receiving stable standard therapy to manage ILD and/or underlying CTD, or to have failed or failed to tolerate first line standard therapy.
5. Participant is capable and willing to self-administer the study medication or has a caregiver who is capable and willing to administer the study medication throughout the study
6. A female participant is eligible to participate if she is not pregnant or breastfeeding, and one of the following conditions applies:

• Is a woman of nonchildbearing potential (WONCBP) OR
• Is a Woman of childbearing potential (WOCBP) and using a contraceptive method that is highly effective, with a failure rate of less than (<)1%

1. Capable of giving signed informed consent

Exclusion criteria:

1. Diagnosis of ILD other than CTD-ILD.
2. Primary diagnosis of Systemic Sclerosis (SSc).
3. Participants with rapidly progressive disease (absolute drop of 10% or more of FVC between screening and baseline visit and/or recent pulmonary hospitalization).

FVC less than or equal to 45% of predicted, or a Diffusing Capacity of the lung for Carbon Monoxide (DLco) (corrected for hemoglobin) less than or equal to 40% of predicted at screening

1. History or presence of diffuse alveolar hemorrhage (DAH) or other confounding pulmonary disease, signs, or symptoms
2. Pulmonary arterial hypertension requiring therapy, as determined by the investigator at, or prior to first day of dosing (Day 1)
3. Dependence on continuous oxygen supplementation
4. History or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematologic, or neurological disorders capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study intervention or interfering with the interpretation of data
5. Obstructive pulmonary disease (pre-bronchodilator Forced Expiratory Volume (FEV1) /FVC <0.7).
6. Significant emphysema on screening or historical HRCT (extent of emphysema exceeds extent of ILD)
7. Confirmed Progressive multifocal leukoencephalopathy (PML) or unexplained new-onset or deteriorating neurologic signs and symptoms
8. Participants with patient health questionnaire (PHQ-9) score greater than or equal to 10, that in the opinion of a mental healthcare professional pose a serious suicide risk, or have any history of suicidal behavior in the last 6 months and/or any suicidal ideation in the last 2 months, or who in the investigator's judgment, poses a significant suicide risk.
9. Lymphoma, leukemia, or any malignancy within the past 5 years except for basal cell or squamous epithelial carcinomas of the skin that have been resected with no evidence of metastatic disease for 3 years

Breast cancer within the past 10 years

1. Major surgery (including joint surgery) within 3 months prior to screening or planned during the duration of the study
2. An active infection, or a history of infections